Steam rooms tanked before they are tiled

The tank under the finish

Liquid membrane over the slab and up the walls past the ceiling junction, reinforcing tape at every corner, screed to a fall of at least 1:50 to the drain, then tile or slate. The ceiling is pitched 3 to 5 degrees so condensate runs to the walls rather than onto whoever is below it.

The membrane needs a full day between coats and a day before tiling. We do not compress that, and a quote that promises a steam room in a fortnight has compressed it.

Water, which varies enormously here

Water hardness differs sharply across South Africa — soft in parts of the Cape, hard on much of the Highveld. We test at the property rather than assuming, because the descaling interval for the generator depends on it and getting it wrong costs a generator.

The generator lives outside the wet room, within about ten metres, somewhere a person can reach with a spanner.

Durban is a different brief

On the KZN coast the room will not dry out on its own. Mechanical extract on a humidistat rather than a timer, ducted out, and a continuous vapour barrier on the warm side with every penetration sealed. A gap in a barrier here traps moisture in the wall, which is worse than none.

In short

• Membrane over slab, walls and ceiling junction, taped at every corner
• Floor falls 1:50, ceiling pitched 3–5°, full cure time respected
• Water tested at the property — hardness varies enormously across the country
• Humidistat-controlled extract on the KZN coast, where nothing dries by itself